Periodontal disease is a highly prevalent disease affecting 90% of the population. Surgery is one of the primary courses of therapy. It assists the patient in home management of the disease but does not result in the restoration of lost periodontium. If surgical therapy could be enhanced to restore the periodontium the patient benefits of the procedure would increase.
Successful periodontal restoration is known to occur if periodontal ligament cells are allowed to colonize root surfaces preferentially over gingival epithelial cells, gingival fibroblasts or osteoblasts. Several studies have been conducted which have elucidated this fundamental mechanism and illustrated its importance in obtaining successful periodontal restoration.
It has been demonstrated that microporous membranes applied beneath periodontal flaps during surgery occlude epithelial cells from apically migrating along the root surface. The subsequent recolonization of the root surface by gingival fibroblasts results in a more selective population of the root surface by periodontal ligament cells.
A number of membranes have been studied including a Millipore.RTM. filter and a Teflon membrane. The Teflon membrane is marketed under the trademark GORE-TEX. A disadvantage of the Millipore.RTM. and GORE-TEX.RTM. membranes is the need for a second surgical entry to remove the membrane. Accordingly, a membrane for periodontal restoration that is biodegradable in the body would eliminate the need for a second surgical entry and be beneficial to the patient and surgeon from both cost and morbidity stand points.
The use of bioabsorbable membranes has been reported. These include microfibrillar collagen, a polygalactin (Vicryl.RTM.) mesh, and a polylactic acid membrane. Results achieved with these biodegradable membranes as well as the Millipore.RTM. and GORE-TEX.RTM. materials to induce guided tissue regeneration have been variable. Precise cutting of membranes and placement over the treatment site can be difficult, time consuming and unpredictable in therapeutic outcome. Higher incidence of infection has also been reported with the nonbiodegradable membranes. The collagen membranes have given variable degradation times in use and there is the concern for an immunological response to a foreign protein with this material.
There has not heretofore been provided a barrier membrane for tissue regeneration comprising a totally synthetic biodegradable material that can be placed in the repair site to form a membrane having the precise geometry needed for that location and the optimum porosity to prevent epithelial tissue downgrowth.